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Factors out the page-mapping function.

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For one less potential source of failure.
This commit is contained in:
Thomas Harte 2018-07-30 22:23:48 -04:00
parent ecb26e3281
commit e9aaa5bbdf
1 changed files with 31 additions and 33 deletions
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64
Machines/AppleII/AppleII.cpp
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@ -173,6 +173,15 @@ template <bool is_iie> class ConcreteMachine:
*/
uint8_t *read_pages_[256]; // each is a pointer to the 256-block of memory the CPU should read when accessing that page of memory
uint8_t *write_pages_[256]; // as per read_pages_, but this is where the CPU should write. If a pointer is nullptr, don't write.
void page(int start, int end, uint8_t *read, uint8_t *write) {
for(int position = start; position < end; ++position) {
read_pages_[position] = read;
if(read) read += 256;
write_pages_[position] = write;
if(write) write += 256;
}
}
// MARK: - The language card.
struct {
@ -186,12 +195,13 @@ template <bool is_iie> class ConcreteMachine:
uint8_t *const ram = alternative_zero_page_ ? aux_ram_ : ram_;
uint8_t *const rom = is_iie ? &rom_[3840] : rom_.data();
for(int target = 0xd0; target < 0x100; ++target) {
uint8_t *const ram_page = &ram[(target << 8) - ((target < 0xe0 && language_card_.bank1) ? 0x1000 : 0x0000)];
uint8_t *const rom_page = &rom[(target << 8) - 0xd000];
write_pages_[target] = has_language_card_ && !language_card_.write ? ram_page : nullptr;
read_pages_[target] = has_language_card_ && language_card_.read ? ram_page : rom_page;
}
page(0xd0, 0xe0,
language_card_.read ? &ram[language_card_.bank1 ? 0xd000 : 0xc000] : rom,
language_card_.write ? nullptr : &ram[language_card_.bank1 ? 0xd000 : 0xc000]);
page(0xe0, 0x100,
language_card_.read ? &ram[0xe000] : &rom[0x1000],
language_card_.write ? nullptr : &ram[0xe000]);
}
// MARK - The IIe's ROM controls.
@ -200,16 +210,13 @@ template <bool is_iie> class ConcreteMachine:
// bool internal_c8_rom_ = false;
void set_card_paging() {
for(int c = 0xc1; c < 0xd0; ++c) {
read_pages_[c] = internal_CX_rom_ ? &rom_[static_cast<size_t>(c << 8) - 0xc100] : nullptr;
}
page(0xc1, 0xd0, internal_CX_rom_ ? rom_.data() : nullptr, nullptr);
if(!internal_CX_rom_) {
if(!slot_C3_rom_) read_pages_[0xc3] = &rom_[0xc300 - 0xc100];
}
}
// MARK - The IIe's auxiliary RAM controls.
bool alternative_zero_page_ = false;
void set_zero_page_paging() {
@ -226,23 +233,20 @@ template <bool is_iie> class ConcreteMachine:
bool read_auxiliary_memory_ = false;
bool write_auxiliary_memory_ = false;
void set_main_paging() {
for(int target = 0x02; target < 0xc0; ++target) {
read_pages_[target] = read_auxiliary_memory_ ? &aux_ram_[target << 8] : &ram_[target << 8];
write_pages_[target] = write_auxiliary_memory_ ? &aux_ram_[target << 8] : &ram_[target << 8];
}
page(0x02, 0xc0,
read_auxiliary_memory_ ? &aux_ram_[0x0200] : &ram_[0x0200],
write_auxiliary_memory_ ? &aux_ram_[0x0200] : &ram_[0x0200]);
if(video_->get_80_store()) {
if(video_ && video_->get_80_store()) {
bool use_aux_ram = video_->get_page2();
for(int target = 0x04; target < 0x08; ++target) {
read_pages_[target] = use_aux_ram ? &aux_ram_[target << 8] : &ram_[target << 8];
write_pages_[target] = use_aux_ram ? &aux_ram_[target << 8] : &ram_[target << 8];
}
page(0x04, 0x08,
use_aux_ram ? &aux_ram_[0x0400] : &ram_[0x0400],
use_aux_ram ? &aux_ram_[0x0400] : &ram_[0x0400]);
if(!video_->get_text()) {
for(int target = 0x10; target < 0x20; ++target) {
read_pages_[target] = use_aux_ram ? &aux_ram_[target << 8] : &ram_[target << 8];
write_pages_[target] = use_aux_ram ? &aux_ram_[target << 8] : &ram_[target << 8];
}
page(0x10, 0x20,
use_aux_ram ? &aux_ram_[0x1000] : &ram_[0x1000],
use_aux_ram ? &aux_ram_[0x1000] : &ram_[0x1000]);
}
}
}
@ -347,7 +351,7 @@ template <bool is_iie> class ConcreteMachine:
break;
case Target::Model::IIe:
rom_size += 3840;
rom_names.push_back("apple2eu.rom");
rom_names.push_back("apple2e.rom");
break;
}
const auto roms = rom_fetcher("AppleII", rom_names);
@ -368,19 +372,13 @@ template <bool is_iie> class ConcreteMachine:
install_card(6, new AppleII::DiskIICard(rom_fetcher, target.disk_controller == Target::DiskController::SixteenSector));
}
// Set up the block that will provide CX ROM access on a IIe.
// cx_rom_block_.read_pointer = rom_.data();
// Set up the default memory blocks. On a II or II+ these values will never change.
// On a IIe they'll be affected by selection of auxiliary RAM.
for(int c = 0; c < 0xc0; ++c) {
read_pages_[c] = write_pages_[c] = &ram_[c << 8];
}
set_main_paging();
set_zero_page_paging();
// Set the whole card area to initially backed by nothing.
for(int c = 0xc0; c < 0xd0; ++c) {
read_pages_[c] = write_pages_[c] = nullptr;
}
page(0xc0, 0xd0, nullptr, nullptr);
// Set proper values for the language card/ROM area.
set_language_card_paging();